The prior art comprises two types of IC test machines (IC TMs): digital test machines (DTMs) and MS test machines (MSTMs).
DTMs are used to test digital DUTs, such as ASICs, while MSTMs can be used for testing MS DUTs.
A DTM can source test vectors to a DUT. Each vector represents a set, or word, of digital values. A test vector specifies values for digital output lines of a DTM that can drive or stimulate a DUT. A DTM can also determine whether the outputs of a DUT are an exact match for an expected set of vectors. Each test or expected vector can typically range anywhere from 1 to 200 bits in width. Outputs of the DUT can generally only be compared to the expected vectors to determine whether the DUT is working correctly. The expected vectors can be generated from the same software used for generating the test vectors.
An MSTM differs from a DTM in several ways. Like a DTM, an MSTM has resources for stimulating a DUT with digital test signals. In addition, an MSTM can also comprise resources, such as DACs, that can produce analog domain stimulus signals. Like a DTM, an MSTM can read or capture outputs of a DUT in the digital domain. In addition, an MSTM can also comprise resources, such as ADCs, that are intended to measure analog domain output signals. Such measurements can be combined to produce a digital representation of an analog waveform. Before a digital representation of an analog waveform can be compared against expected values, it can be necessary for the MSTM to perform digital signal processing (DSP) upon such digital representation. For example, the MSTM can perform a Fast Fourier Transform (FFT).
Because an MSTM often needs to produce and/or process relatively complex digital representations of analog waveforms, it typically includes a general purpose computer (e.g., a microprocessor system) that can be appropriately programmed.
The programming of an MSTM can be complex, causing significant delays in time-to-market for MS ICs. Furthermore, the programming of an MSTM can be non-portable, since it can depend upon the particular hardware resources of the MSTM for which it was written.
In contrast, the test and expected vectors, used in a DTM, can be relatively portable since they can depend only on the resources of the digital DUT. It would be desirable to accomplish MS DUT testing with test and expected vectors possessing a similar level of portability to those of digital DUT testing.